In the related art, a solar cell is under development as a new energy source having less effect on a global environment.
For example, a dye-sensitized type solar cell including an electrolytic solution filled into an interior of a transparent vessel, provided with a photoelectrode formed of a porous semiconductor including a dye adsorbed thereto and a counter electrode, and configured to release electrons from the dye irradiated with solar light and get electric energy therefrom.
The solar cell of this type does not require a high-vacuum chamber or the like for manufacture, and hence causes a low-impact in terms of facilities, and achieves a low-cost manufacture.
By the way, the solar cell is confronted with the challenge of being incapable of supplying power during the night because no power is generated due to a configuration thereof which generates power by solar light.
In order to handle such challenge, a solar cell provided with a power storage function added thereto so as to supply power stably during both the day and the night is known (Patent Literature 1).
FIG. 15 is a cross-sectional view illustrating a configuration of a solar cell described in Patent Literature 1.
A solar cell 91 includes a power generating portion 92, a power storage portion 93, and a common electrode 95.
The power generating portion 92 constitutes a so-called “Grätzel Cell” type dye-sensitized type solar cell by including a photoelectrode 94 including photosensitizing dyes 94d adsorbed to a semiconductor layer 94e formed on a translucent substrate, a first electrolytic solution 97 filled between the photoelectrode 94 and the common electrode 95, and a catalyst layer 96 formed on one of side surfaces of the common electrode 95.
In contrast, the power storage portion 93 includes a first conductive polymeric molecule layer 910 on a side opposite to the catalyst layer 96 of the common electrode 95, a second electrolytic solution 98 filled therein, and an power storage portion electrode 99 insulated thereby and having a second conductive polymeric molecule layer 911.
In FIG. 15, reference numeral 100 denotes a load.
When the power generating portion 92 receives solar light and generates power, generated electrons move to the power storage portion electrode 99 via the photoelectrode 94, cause undoping in the second conductive polymeric molecule layer 911 of the power storage portion electrode 99, and release anion into the second electrolytic solution 98. The released anion causes doping in the first conductive polymeric molecule layer 910, and stores holes in the first conductive polymeric molecule layer 910. In this configuration, the power is stored between the common electrode 95 and the power storage portion electrode 99. According to the solar cell 91, when the light is received, the power generating portion 92 generates power and supplies the power and, simultaneously, stores electrons in the power storage portion 93, and when reception of the light is stopped, power can be supplied by releasing electrons from the power storage portion 93, so that stable power supply is achieved even when light is reduced.
In this manner, an invention which makes an attempt to store power by using an electrolytic solution in the dye-sensitized solar cell is known in the related art.